http://www.ck12.org Chapter 20. Entropy and Free Energy
CHAPTER
(^20) Entropy and Free Energy
Chapter Outline
20.1 Entropy
20.2 SPONTANEOUSREACTIONS ANDFREEENERGY
20.3 FREEENERGY ANDEQUILIBRIUM
20.4 REFERENCES
The two paintings above represent two distinct movements in twentieth-century abstract art. Pollock was a proponent
of abstract expressionism, mainly a post-World War II development. He was well-known for his drip paintings,
where paint is dripped or poured on the canvas. Mondrian was strongly influenced by the earlier Cubist movement,
which was characterized by extensive use of geometric forms. We can see the high level of disorder in Pollock’s
work, generated by random activity. On the other hand, the paintings by Mondrian represent a high level of structure
and order.
The world we live in has aspects of order and disorder. We see order in the regular crystalline structure of solid
sodium chloride and disorder in the random spattering of raindrops on a sidewalk. We also can observe changes in
the amount of random movement exhibited by a single substance. For example, ice is highly ordered; each molecule
of water is held rigidly in place by a network of hydrogen bonds. As the ice melts, the molecules gain more freedom
of movement. They still cluster together into a liquid, but the individual molecules are free to move past one another
and exchange hydrogen bonding partners. As the water vaporizes, its movement becomes even less restricted. No
longer bound by intermolecular interactions, each molecule of water is free to move in essentially any direction. In
this chapter, we will be discussing the concept of entropy, which quantifies order and disorder as pertains to chemical
processes.
Le f t:Image co pyright Lauren Jade Goudie, 2014 .www.shutterstock.com.U sed under licenses f rom Shutterstock.com.
Right:Image co pyright Fedorov Oleksiy, 2014 .www.shutterstock.com.U sed under licenses f rom Shutterstock.com.